This thunderstorm was right at flight level. See other beautiful phenomena from the Bahamas.
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Costa Rica is a small country in Central America, having an area of 51,100 square kilometers. That means it is approximately the size of West Virginia! Despite its less than intimidating land mass, Costa Rica has been celebrated around the globe for being an excellent example of stability, progressive health care, and conservation. Over 12% of the country has been declared national park territory. There is an amazing diversity and abundance of plants and animals in this tropical region. One of the most fascinating aspects of Costa Rica, however, is its volcanoes.
Costa Rica sits over part of the Pacific Ring Fire Circle. This circle can be visualized as a ring around the Pacific Ocean, intersecting the eastern coast of Asia and the western coast of the Americas. Earthquakes and volcanic activity are common along this line as a result of plate tectonics (which I will describe more fully later). In fact, more than half of the worldÕs volcanoes are a part of the Pacific Ring of Fire. The thick band of the Pacific Ring crosses Costa Rica, and is the reason for the large number of volcanoes in the country. If you look at a physical map of the country, you can see a line of mountains cutting across the land at an angle.
Costa Rica is home to over 60 extinct and dormant volcanoes and 42 active volcanoes (Baker 2007). Some of the most significant (in terms of size and activity) are Arenal, Rincon de la Vieja, Irazu, Poas, Miravalles, and Turrialba. Miravalles is located in the northern part of Costa Rica, while the other four are within a few hours drive of San Jose. The region around San Jose is known as the Meseta Central. It is the most populated area in Costa Rica and has rich, fertile soil as a result of the many volcanic eruptions that have distributed nutrient-rich ash over the many years. There are many coffee plantations here because of these advantageous conditions.
Irazu is the largest volcano in Costa Rica. It rises 11,257 ft from its base and has multiple craters. On a clear day, it is said that a person can view both the Pacific Ocean and the Caribbean Sea from the peak. Irazu has been responsible for many catastrophic eruptions in the past, one of the most significant occurring in 1963. On the day John F. Kennedy arrived in Costa Rica for a state visit, Irazu sent ash and lava spewing up from out of the earth. Ash rained down on the Meseta Central for two whole years.
Volcan Poas has three craters, two of which are dormant and contain clear lakes that are surrounded by green vegetation. One of the lakes, Lake Botos (or Botos Lagoon) is home to a diverse number of exotic birds and other organisms. One of the most significant is the Resplendent Quetzal, an incredibly beautiful endangered bird. The third crater measures approximately one mile in diameter and has a green, sulphurous lake at its bottom. This lake is known as Laguna Caliente and is extremely acidic. It causes the trees in the surrounding area to have stunted growth as a result of the acidic rain it creates. Poas has always been known for having many eruptions, but its activity has increased even more in the past thirty years. Although it no longer emits magma, it continuously spits geysers into the air.
At 4,000 years and 5,479 ft, Arenal is the youngest volcano in Costa Rica. It was believed to be dormant, until 1968 when an enormous eruption took place that lasted several days. The force of the eruption created three new craters in the mountain. Ever since 1968, Arenal has had frequent, minor emissions of smoke, rocks, and lava, occurring chiefly on the summit and western side. It is one of the most active volcanoes in the world. Because of its many small-scale eruptions and perfect, conical shape, Volcan Arenal attracts many tourists. It also provides heat for the popular hot springs in the area. Arenal is located near many prime sightseeing locations, including La Fortuna Falls, the Monteverdi Cloud Forest, and Arenal Lake.
So how did all of these lava-belching land masses come into existence? Tectonic plates are the basis for much of volcanic activity. The earthÕs crust is divided into twelve different sections. These plates are slowly moving in different directions. Theory suggests that the movement is caused by convection currents in the mantle. Costa Rica is located on the Caribbean Plate, which is in conjunction with the Cocos Plate to the west. Along the boundaries of tectonic plates, there is a great amount of seismic activity. As the plates are pushed or pulled apart, volcanoes and mountains often form.
If two tectonic plates are converging, then one (the denser plate) undergoes subduction. As the plate slides downward, it is heated by the earthÕs mantle causing the plate to melt and become magma. Heat rises, so the scalding magma pushes upward towards the earthÕs surface. Eventually the pressure will cause the liquid rock to erupt into the air. Each eruption leaves a layer of lava that solidifies, building a cone that grows over time.
In some cases, volcanoes can form from diverging plates. These are usually much less dramatic. The tectonic plates pull away from each other leaving a gap through which magma from the mantle seeps through. Many of these types of volcanoes are found in the oceans deep underwater. Finally, some volcanoes are formed from hotspots, far from the edges of the plates. A hotspot is a place where large amounts of magma from deep within the mantle rise to the surface (Bunce 2000). Pressure causes the release of magma and volcanoes form directly over the hotspot. Since the volcanoes are located on a moving tectonic plate, they will eventually be carried away from the hotspot and become extinct. A new volcano will form on the crust that has been carried to the hotspot. The Hawaiian islands are a good example of a chain of volcanoes formed in this way.
Volcanoes can emit gas, lava (magma that has reached the surface), and/or tephra (rock fragments including ash and boulders) during an eruption. The different shapes that volcanoes assume are related to the substances that are emitted from the volcano. Most of the volcanoes in Costa Rica (and in the world) are stratovolcanoes, or composite cone volcanoes. These are volcanoes that have varied types of lava and also have varied types of eruptions. They generally emit large amounts of ash, and the lava is thick and viscous due to large amounts of silica in it. Stratovolcanoes are usually tall and steep because the thick lava does not travel far. They also tend to have more secondary vents than other types of volcanoes. Other types of volcanoes include ash and cinder, acid lava, and shield cones.
Whatever the type of volcano, they invariably leave some kind of effect on their environment. Most of the short-term effects tend to be destructive. Accompanying an eruption are minor earthquakes, toxic gases, and lahars. Lahars are massive mudslides. If there is a lake inside the crater of the volcano, the water will be released during an eruption. The water flows downhill along with ash and debris, continuously gathering speed. Volcanoes in cold regions can also create lahars since magma, or even just hot gases, quickly melts all of the nearby snow. In fact lahars, can often be more dangerous than lava flows because they are so much faster and are capable of burying entire towns. Lava flows are very slow, but can burn anything in their path. Pyroclastic flows are combinations of hot ash and dust that travel quickly and cause much destruction. Other dangers include avalanches, tsunamis, and ash. Ash can accumulate on buildings and can cause them to collapse if the weight becomes too much. It can also stall engines on aircraft.
Finally, volcanoes can significantly alter our climate. If an eruption is large enough, the ash and dust particles can linger in the atmosphere. The particles can either increase or decrease the earthÕs temperature depending on their size. Large particles trap heat whereas small particles limit the amount of sunlight that reaches the planet and cause the earth to cool (Rowland 2005). This is one theory about what caused the extinction of the dinosaurs.
Volcanoes arenÕt all bad, however. They have many positive roles in the environment. One of the most noticeable is soil fertility. As the ash and dust decompose, they provide valuable nutrients to the soil, promoting plant growth. For example, the Meseta Central is an excellent agricultural site because of its close proximity to the volcanoes. The volcanoes also bring valuable minerals, metals, and gems from within the mantle to the surface. One positive effect that is sometimes overlooked is the creation of islands. Islands are important ecosystems because they lead to speciation. Plants and animals that travel to the newly formed islands undergo changes over time that make them better adapted to their new environment. As a result, new species are born that have unique characteristics and capabilites.
Another benefit of volcanoes, which is only just recently being taken advantage of, is geothermal energy. People are now harnessing the energy produced by steam vents and converting it into energy that can be used by humans. This is another exciting and useful application of science. Geothermal energy is also a safer and cleaner alternative to fossil fuels. Costa Rica is one of twenty countries that harvests geothermal energy. Currently, geothermal installed power accounts for 15.1% of the countryÕs produced electricity (Iglesias 2008). The main operating site is at Miravalles, although there are plans to use the Rincon de la Vieja Volcano as well.
Finally, volcanoes have made the earth what it is today. Water vapor is one of the gases released by volcanoes. Over millions of years, the water vapor accumulated in the atmosphere in huge clouds. As the earth cooled, the water vapor condensed to create oceans. Volcanoes also played an important role in the cooling of the earth by releasing heat from deep within the core. Other gases released by volcanoes have created the earthÕs atmosphere.
Humans have always had a tenuous relationship with volcanoes. We are fascinated by their beauty and frightened of their deadly potential. We usually focus on their negative impacts and forget to look at the benefits, and most people certainly donÕt think about the fact that humans (along with the rest of life) may not have come into existence without volcanoes. Volcanoes play an important role on the global scale and also on a smaller scale. In Costa Rica, they significantly affect the country by adding to the soil fertility, contributing to geothermal energy, and attracting tourists.
References
Baker, Christopher. (2007). Moon Handbooks- Costa Rica. Emeryville: Avalon Travel Publishing. P. 516-518.
Blong, R.J.(1984). Volcanic hazards: A source book on the effects of eruptions. Orlando: Academic Press. P. 424.
Bunce, Vincent. (2000). Restless Planet- Volcanoes. Austin: Steck-Vaughn Company. P. 1-23, 40-41.
Camp, Vic. ÒHow Volcanoes Work.Ó http://www.geology.sdsu.edu/how_volcanoes_work/Home.html. Last updated 03/31/2006. Sponsored by NASA.
Campbell N, Reece J. (2005). Biology- Seventh Edition. San Francisco: Benjamin Cummings. Pp. 1223-1224.
Iglesias E and Malolepszy Z. (2008). ÒElectricity Generation.Ò http://iga.igg.cnr.it/geoworld/geoworld.php?sub=elgen&country=costarica. Last updated 05/09/2008. Sponsored by the International Geothermal Association.
Kricher, John. (1997). A Neotropical Companion. Princeton University Press. P. 52,57.
Reagan M, Gill J, Malavassi E, Garcia M. (1987).ÒChanges in magma composition at Arenal volcano, Costa Rica, 1968Ð1985: Real-time monitoring of open-system differentiation.Ó Bulletin of Volcanology. 49 (1) Pp.415-434.
Rowland S, Mattox S. ÒEffect of Volcanoes.Ó (2005). http://volcano.und.edu/vwdocs/frequent_questions/top_101/Effects.html .Sponsored by North Dakota and Oregon Space Grant Consortia.
Topinka, Lyn. ÒCosta Rica Volcanoes and Volcanics.Ó
http://vulcan.wr.usgs.gov/Volcanoes/CostaRica/framework.html. Created on 02/17/2004. Sponsored by USGS
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